Guide apparatus for tangential entry into suprachoroidal space

ABSTRACT

An apparatus includes a body and a pair of rigid legs extending from the body. The body includes an engagement feature configured to engage a deployment instrument. The legs are parallel with each other. Each leg has a sharp tip. The legs both extend along a plane. The body defines a guide opening. The guide opening is oriented transversely relative to the plane associated with the legs. The guide opening is sized to receive a cannula having a generally flat profile. The guide opening is configured to guide the cannula through a sclerotomy at a substantially tangential orientation.

PRIORITY

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/351,620, entitled “Cannula Guide for Tangential Entry intoSuprachoroidal Space,” filed Jun. 17, 2016, the disclosure of which isincorporated by reference herein.

BACKGROUND

The human eye comprises several layers. The white outer layer is thesclera, which surrounds the choroid layer. The retina is interior to thechoroid layer. The sclera contains collagen and elastic fiber, providingprotection to the choroid and retina. The choroid layer includesvasculature providing oxygen and nourishment to the retina. The retinacomprises light sensitive tissue, including rods and cones. The maculais located at the center of the retina at the back of the eye, generallycentered on an axis passing through the centers of the lens and corneaof the eye (i.e., the optic axis). The macula provides central vision,particularly through cone cells.

Macular degeneration is a medical condition that affects the macula,such that people suffering from macular degeneration may experience lostor degraded central vision while retaining some degree of peripheralvision. Macular degeneration may be caused by various factors such asage (also known as “AMD”) and genetics. Macular degeneration may occurin a “dry” (nonexudative) form, where cellular debris known as drusenaccumulates between the retina and the choroid, resulting in an area ofgeographic atrophy. Macular degeneration may also occur in a “wet”(exudative) form, where blood vessels grow up from the choroid behindthe retina. Even though people having macular degeneration may retainsome degree of peripheral vision, the loss of central vision may have asignificant negative impact on the quality of life. Moreover, thequality of the remaining peripheral vision may be degraded and in somecases may disappear as well. It may therefore be desirable to providetreatment for macular degeneration in order to prevent or reverse theloss of vision caused by macular degeneration. In some cases it may bedesirable to provide such treatment in a highly localized fashion, suchas by delivering a therapeutic substance in the subretinal layer (underthe neurosensory layer of the retina and above the retinal pigmentepithelium) directly adjacent to the area of geographic atrophy, nearthe macula. However, since the macula is at the back of the eye andunderneath the delicate layer of the retina, it may be difficult toaccess the macula in a practical fashion.

While a variety of surgical methods and instruments have been made andused to treat an eye, it is believed that no one prior to the inventorshas made or used the invention described in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims which particularly pointout and distinctly claim this technology, it is believed this technologywill be better understood from the following description of certainexamples taken in conjunction with the accompanying drawings, in whichlike reference numerals identify the same elements and in which:

FIG. 1 depicts a perspective view of an exemplary instrument forsubretinal administration of a therapeutic agent from a suprachoroidalapproach;

FIG. 2 depicts a perspective view of the distal end of an exemplarycannula that may be incorporated into the instrument of FIG. 1;

FIG. 3A depicts a cross-sectional side view of the cannula of FIG. 2,with the cross-section taken along line 3-3 of FIG. 2, with a needle ina first longitudinal position;

FIG. 3B depicts a cross-sectional side view of the cannula of FIG. 2,with the cross-section taken along line 3-3 of FIG. 2, with the needlein a second longitudinal position;

FIG. 4A depicts a cross-sectional view of an eye of a patient, with achandelier installed in the eye;

FIG. 4B depicts a cross-sectional view of the eye of FIG. 4A, with asuture loop attached to the eye, and with a sclerotomy being performed;

FIG. 4C depicts a cross-sectional view of the eye of FIG. 4A, with theinstrument of FIG. 1 being inserted through the sclerotomy opening andin between the sclera and choroid of the eye;

FIG. 4D depicts a cross-sectional view of the eye of FIG. 4A, with theinstrument of FIG. 1 under direct visualization at the back of the eye,between the sclera and choroid;

FIG. 4E depicts a cross-sectional view of the eye of FIG. 4A, with theneedle of the instrument of FIG. 1 being advanced under directvisualization at the back of the eye, pressing against the outer surfaceof the choroid causing the choroid to “tent”;

FIG. 4F depicts a cross-sectional view of the eye of FIG. 4A, with theneedle dispensing a leading bleb under direct visualization at the backof the eye, the needle between the sclera and choroid, and the leadingbleb in the subretinal space between the choroid and a retina;

FIG. 4G depicts a cross-sectional view of the eye of FIG. 4A, with theneedle dispensing a therapeutic agent to the eye at the back of the eye,between the sclera and choroid;

FIG. 5A depicts a detailed cross-sectional view of the eye of FIG. 4Adepicted in the state shown in FIG. 4E;

FIG. 5B depicts a detailed cross-sectional view of the eye of FIG. 4Adepicted in the state shown in FIG. 4F;

FIG. 5C depicts a detailed cross-sectional view of the eye of FIG. 4Adepicted in the state shown in FIG. 4G;

FIG. 6 depicts a perspective view of an exemplary guide tack that may beused to guide the cannula of FIG. 2 during performance of the procedureshown in FIGS. 4A-4G and 5A-5C;

FIG. 7 depicts another perspective view of the guide tack of FIG. 6;

FIG. 8A depicts a top plan view of an eye of a patient, with a first endof a marking and deployment instrument being used to mark a guide tackdeployment site on the eye;

FIG. 8B depicts a top plan view of the eye of FIG. 8A, with a second endof the marking and deployment instrument of FIG. 8A being used to deploya guide tack in the eye while marking a sclerotomy site on the eye;

FIG. 8C depicts a top plan view of the eye of FIG. 8A, with the guidetack of FIG. 6 deployed in the eye, and with a sclerotomy site mark onthe eye;

FIG. 8D depicts a top plan view of the eye of FIG. 8A, with a sclerotomybeing provided at the sclerotomy site of FIG. 8C;

FIG. 8E depicts a top plan view of the eye of FIG. 8A, with the cannulaof FIG. 2 being guided into the sclerotomy of FIG. 8D via the guide tackof FIG. 6;

FIG. 9 depicts a perspective view of an exemplary alternative guide tackthat may be used to guide the cannula of FIG. 2 during performance ofthe procedure shown in FIGS. 4A-4G, 5A-5C, and 8A-8E;

FIG. 10 depicts another perspective view of the guide tack of FIG. 9;

FIG. 11 depicts a front elevational view of a distal portion of a leg ofthe guide tack of FIG. 9;

FIG. 12 depicts a side elevational view of a distal portion of a leg ofthe guide tack of FIG. 9;

FIG. 13 depicts a front elevational view of the guide tack of FIG. 9;

FIG. 14 depicts a bottom plan view of the guide tack of FIG. 9;

FIG. 15 depicts a perspective view of another exemplary alternativeguide tack that may be used to guide the cannula of FIG. 2 duringperformance of the procedure shown in FIGS. 4A-4G, 5A-5C, and 8A-8E;

FIG. 16 depicts another perspective view of the guide tack of FIG. 15;

FIG. 17 depicts a front elevational view of the guide tack of FIG. 15;

FIG. 18 depicts a perspective view of another exemplary alternativeguide tack that may be used to guide the cannula of FIG. 2 duringperformance of the procedure shown in FIGS. 4A-4G, 5A-5C, and 8A-8E;

FIG. 19 depicts another perspective view of the guide tack of FIG. 18;

FIG. 20 depicts a front elevational view of the guide tack of FIG. 18;

FIG. 21 depicts a perspective view of another exemplary alternativeguide tack that may be used to guide the cannula of FIG. 2 duringperformance of the procedure shown in FIGS. 4A-4G, 5A-5C, and 8A-8E;

FIG. 22 depicts another perspective view of the guide tack of FIG. 21;

FIG. 23 depicts a perspective view of an exemplary alternative head thatmay be incorporated into any of the guide tacks described herein;

FIG. 24 depicts a front elevational view of the head of FIG. 23;

FIG. 25 depicts a perspective view of another exemplary alternative headthat may be incorporated into any of the guide tacks described herein;

FIG. 26 depicts a front elevational view of the head of FIG. 25;

FIG. 27 depicts a side elevational view of the head of FIG. 25;

FIG. 28 depicts a cross-sectional view of the head of FIG. 25, takenalong line 28-28 of FIG. 26;

FIG. 29 depicts a partial cross-sectional view of an upper portion ofanother exemplary alternative guide tack that may be used to guide thecannula of FIG. 2 during performance of the procedure shown in FIGS.4A-4G, 5A-5C, and 8A-8E;

FIG. 30 depicts a partial front elevational view of an upper portion ofanother exemplary alternative guide tack that may be used to guide thecannula of FIG. 2 during performance of the procedure shown in FIGS.4A-4G, 5A-5C, and 8A-8E;

FIG. 31 depicts a partial cross-sectional view of an upper portion ofanother exemplary alternative guide tack that may be used to guide thecannula of FIG. 2 during performance of the procedure shown in FIGS.4A-4G, 5A-5C, and 8A-8E;

FIG. 32 depicts a perspective view of another exemplary alternativeguide tack that may be used to guide the cannula of FIG. 2 duringperformance of the procedure shown in FIGS. 4A-4G, 5A-5C, and 8A-8E;

FIG. 33 depicts another perspective view of the guide tack of FIG. 32;

FIG. 34 depicts a perspective view of another exemplary alternativeguide tack that may be used to guide the cannula of FIG. 2 duringperformance of the procedure shown in FIGS. 4A-4G, 5A-5C, and 8A-8E;

FIG. 35 depicts another perspective view of the guide tack of FIG. 34;

FIG. 36 depicts a perspective view of an exemplary marking anddeployment instrument that may be used during performance of theprocedure shown in FIGS. 8A-8E;

FIG. 37 depicts another perspective view of the marking and deploymentinstrument of FIG. 36;

FIG. 38 depicts a partial perspective view of a first end of the markingand deployment instrument of FIG. 36;

FIG. 39 depicts a partial perspective view of a second end of themarking and deployment instrument of FIG. 36;

FIG. 40 depicts a partial perspective view of the second end of themarking and deployment instrument of FIG. 36, with the guide tack ofFIG. 6 mounted thereon;

FIG. 41A depicts a partial perspective view of the second end of themarking and deployment instrument of FIG. 36, with a slider andattachment pin in a distal position;

FIG. 41B depicts a partial perspective view of the second end of themarking and deployment instrument of FIG. 36, with the slider andattachment pin in a proximal position;

FIG. 42 depicts a perspective view of an exemplary alternative markingand deployment instrument that may be used during performance of theprocedure shown in FIGS. 8A-8E;

FIG. 43 depicts another perspective view of the marking and deploymentinstrument of FIG. 42;

FIG. 44 depicts a perspective view of the distal end of an exemplaryalternative marking instrument;

FIG. 45 depicts a perspective view of the distal end of anotherexemplary alternative marking instrument;

FIG. 46 depicts a perspective view of the distal end of anotherexemplary alternative marking instrument;

FIG. 47 depicts a perspective view of the distal end of anotherexemplary alternative marking instrument;

FIG. 48 depicts a schematic view of an eye of a patient, with anexemplary set of markings thereon;

FIG. 49 depicts a schematic view of an eye of a patient, with anotherexemplary set of markings thereon;

FIG. 50 depicts a schematic view of an eye of a patient, with anotherexemplary set of markings thereon;

FIG. 51 depicts a schematic view of an eye of a patient, with anotherexemplary set of markings thereon;

FIG. 52 depicts a schematic view of an eye of a patient, with anotherexemplary set of markings thereon;

FIG. 53 depicts a schematic view of an eye of a patient, with anotherexemplary set of markings thereon;

FIG. 54 depicts a schematic view of an eye of a patient, with anotherexemplary set of markings thereon; and

FIG. 55 depicts a schematic view of an eye of a patient, with anotherexemplary set of markings thereon.

The drawings are not intended to be limiting in any way, and it iscontemplated that various embodiments of the technology may be carriedout in a variety of other ways, including those not necessarily depictedin the drawings. The accompanying drawings incorporated in and forming apart of the specification illustrate several aspects of the presenttechnology, and together with the description serve to explain theprinciples of the technology; it being understood, however, that thistechnology is not limited to the precise arrangements shown.

DETAILED DESCRIPTION

The following description of certain examples of the technology shouldnot be used to limit its scope. Other examples, features, aspects,embodiments, and advantages of the technology will become apparent tothose skilled in the art from the following description, which is by wayof illustration, one of the best modes contemplated for carrying out thetechnology. As will be realized, the technology described herein iscapable of other different and obvious aspects, all without departingfrom the technology. Accordingly, the drawings and descriptions shouldbe regarded as illustrative in nature and not restrictive.

It is further understood that any one or more of the teachings,expressions, embodiments, examples, etc. described herein may becombined with any one or more of the other teachings, expressions,embodiments, examples, etc. that are described herein. Thefollowing-described teachings, expressions, embodiments, examples, etc.should therefore not be viewed in isolation relative to each other.Various suitable ways in which the teachings herein may be combined willbe readily apparent to those of ordinary skill in the art in view of theteachings herein. Such modifications and variations are intended to beincluded within the scope of the claims.

For clarity of disclosure, the terms “proximal” and “distal” are definedherein relative to a surgeon or other operator grasping a surgicalinstrument having a distal surgical end effector. The term “proximal”refers the position of an element closer to the surgeon or otheroperator and the term “distal” refers to the position of an elementcloser to the surgical end effector of the surgical instrument andfurther away from the surgeon or other operator.

I. Exemplary Instrument for Subretinal Administration of TherapeuticAgent

FIG. 1 shows an exemplary instrument (10) that is configured for use ina procedure for the subretinal administration of a therapeutic agent toan eye of a patient from a suprachoroidal approach. Instrument (10)comprises a body (20) and a flexible cannula (50) extending distallyfrom body (20). Cannula (50) of the present example has a generallyrectangular cross section, though any other suitable cross-sectionalprofile (e.g., elliptical, etc.) may be used. Cannula (50) is generallyconfigured to support a needle (100) that is slidable within cannula(50), as will be described in greater detail below.

In the present example, cannula (50) comprises a flexible material suchas Polyether block amide (PEBA), which may be manufactured under thetrade name PEBAX. Of course, any other suitable material or combinationof materials may be used. Also in the present example, cannula (50) hasa cross-sectional profile dimension of approximately 2.0 mm by 0.8 mm,with a length of approximately 80 mm. Alternatively, any other suitabledimensions may be used. As will be described in greater detail below,cannula (50) is flexible enough to conform to specific structures andcontours of the patient's eye, yet cannula (50) has sufficient columnstrength to permit advancement of cannula (50) between the sclera andchoroid of patient's eye without buckling. By way of example only,cannula (50) may be configured and operable in accordance with at leastsome of the teachings of U.S. Pub. No. 2015/0223977, entitled “Methodand Apparatus for Subretinal Administration of Therapeutic Agent,”published Aug. 13, 2015, the disclosure of which is incorporated byreference herein.

As can be seen in FIGS. 2-3B and 6, cannula (50) comprises a body (52),a closed distal end (54), and a lateral opening (56) that is locatedproximal to distal end (54). In the present example, distal end (54) hasa rounded configuration. It should be understood that distal end (54)may have any suitable kind of curvature. It should also be understoodthat distal end (54) may have any other suitable kind of configuration(e.g., beveled, etc.). In the present example, distal end (54) isconfigured to provide separation between the sclera and choroid layersto enable cannula (50) to be advanced between such layers while notinflicting trauma to the sclera or choroid layers. Also in the presentexample, the region of body (52) that defines lateral opening (56) isbeveled, as best seen in FIGS. 3A-3B. Alternatively, the edge of lateralopening (56) may have any other suitable configuration.

As best seen in FIGS. 3A-3B, a needle guide (60) is disposed within thehollow interior of cannula (50). By way of example only, needle guide(60) may be secured within cannula (50) by a press or interference fit,by adhesives, by mechanical locking mechanisms, and/or in any othersuitable fashion. Needle guide (60) includes a curved distal end (62)that leads to lateral opening (56) of cannula (50), such that a lumen(64) of needle guide (60) distally terminates at lateral opening (56).The portion of needle guide (60) that is proximal to distal end (62) issubstantially straight. Needle guide (60) may be formed of plastic,stainless steel, and/or any other suitable biocompatible material(s).

Needle (100) of the present example has a sharp distal tip (102) anddefines a lumen (104). Distal tip (102) of the present example has alancet configuration. In some other versions, distal tip (102) has atri-bevel configuration or any other configuration as described in U.S.Pub. No. 2015/0223977, entitled “Method and Apparatus for SubretinalAdministration of Therapeutic Agent,” published Aug. 13, 2015, thedisclosure of which is incorporated by reference herein. Still othersuitable forms that distal tip (102) may take will be apparent to thoseof ordinary skill in the art in view of the teachings herein. Needle(100) of the present example comprises a stainless steel hypodermicneedle that is sized to deliver the therapeutic agent while being smallenough to minimize incidental trauma as needle (100) penetrates tissuestructures of the patient's eye, as will be described in greater detailbelow. While stainless steel is used in the present example, it shouldbe understood that any other suitable material(s) may be used, includingbut not limited to nitinol, etc.

By way of example only, needle (100) may be 35 gauge with a 100 μm innerdiameter, although other suitable sizes may be used. For instance, theouter diameter of needle (100) may fall within the range of 27 gauge to45 gauge; or more particularly within the range of 30 gauge to 42 gauge:or more particularly within the range of 32 gauge to 39 gauge. Asanother merely illustrative example, the inner diameter of needle (100)may fall within the range of approximately 50 μm to approximately 200μm; or more particularly within the range of approximately 50 μm toapproximately 150 μm; or more particularly within the range ofapproximately 75 μm to approximately 125 μm.

Needle (100) is slidably disposed within lumen (64) of needle guide(60). Needle guide (60) is generally configured to direct needle (100)upwardly along an exit axis (EA) that is obliquely oriented relative tothe longitudinal axis (LA) of cannula (50) through lateral opening (56)of cannula (50). This is shown in the sequence depicted in FIGS. 3A-3B,in which FIG. 3A shows needle (100) in a proximal position (where distaltip (102) of needle (100) is fully contained in lumen (64) of needleguide (60)); and FIG. 3B shows needle (100) in a distal position (wheredistal tip (102) of needle (100) is outside of needle guide (60)). Whileneedle (100) is flexible, needle (100) of the present example isresiliently biased to assume a straight configuration. Thus, as shown inFIG. 3B, the portion of needle (100) that extends outside of cannula(50) and needle guide (60) is substantially straight, extending alongexit axis (EA). In particular, at least a substantial length of theportion of needle (100) that extends outside of cannula (50) and needleguide (60) is coaxially aligned with exit axis (EA).

It should be understood that the depiction of exit axis (EA) in FIGS.3A-3B may be somewhat exaggerated, for illustrative purposes only. Insome versions, curved distal end (62) is configured to direct needle(100) along an exit axis (EA) that extends distally from cannula (50) atan angle of approximately 7° to approximately 9° relative to thelongitudinal axis (LA) of cannula (50). It should be understood thatsuch an angle may be desirable to deflect needle (100) in a direction toensure penetration of needle into the choroid and to minimize thepossibility of needle (100) continuing beneath the choroid through thesuprachoroidal space (as opposed to penetrating through the choroid) andthe possibility of retinal perforation. By way of further example only,curved distal portion (88) may urge needle (100) to exit cannula (50)along an exit axis (EA) that is oriented at an angle within the range ofapproximately 5° to approximately 30° relative to the longitudinal axis(LA) of cannula (50); or more particularly within the range ofapproximately 5° to approximately 20° relative to the longitudinal axis(LA) of cannula (50); or more particularly within the range ofapproximately 5° to approximately 10° relative to the longitudinal axis(LA) of cannula (50).

As shown in FIG. 1, instrument (10) of the present example furthercomprises an actuation knob (26) located at the proximal end of body(20). Actuation knob (26) is rotatable relative to body (20) to therebyselectively translate needle (100) longitudinally relative to cannula(50). In particular, actuation knob (26) is rotatable in a first angulardirection to drive needle (100) distally relative to cannula (50); andin a second angular direction to drive needle (100) proximally relativeto cannula (50). By way of example only, instrument (10) may providesuch functionality through knob (26) in accordance with at least some ofthe teachings of U.S. Pub. No. 2015/0223977, entitled “Method andApparatus for Subretinal Administration of Therapeutic Agent,” publishedAug. 13, 2015, the disclosure of which is incorporated by referenceherein. Alternatively, any other suitable kind of actuation feature(s)may be used to drive needle (100) longitudinally relative to cannula(50).

In the present example, knob (26) is rotatable through a complete rangeof motion that corresponds to advancement of needle (100) to a positionrelative to cannula (50) to a predetermined amount of penetration withinan eye of a patient. In other words, instrument (10) is configured suchthat an operator rotates knob (26) until knob (26) can no longer rotate,or until knob (26) begins to slip or “freewheel” in a clutch assembly,to properly position needle (100) within an eye of a patient. In someexamples, the predetermined amount of advancement of needle (100)relative to cannula (50) is between approximately 0.25 mm toapproximately 10 mm; or more particularly within the range ofapproximately 0.1 mm to approximately 10 mm; or more particularly withinthe range of approximately 2 mm to approximately 6 mm; or moreparticularly to approximately 4 mm.

In addition or in the alternative, instrument (10) may be equipped withcertain tactile feedback features to indicate to an operator when needle(100) has been advanced to certain predetermined distances relative tocannula (50). Accordingly, an operator may determine the desired depthof penetration of needle (100) into a patient's eye based on directvisualization of indicia on instrument and/or based on tactile feedbackfrom instrument (10). Of course, such tactile feedback features may becombined with the present example, as will be apparent to those ofordinary skill in the art in view of the teachings herein.

As also shown in FIG. 1, a pair of supply tubes (30, 40) extendproximally from actuator knob (26). In the present example, first supplytube (30) is configured to couple with a source of bleb fluid (340)(e.g., BSS); while second supply tube (40) is configured to couple witha source of therapeutic agent (341). It should be understood that eachfluid supply tube (30, 40) may include a conventional luer featureand/or other structures permitting fluid supply tubes (30, 40) to becoupled with respective fluid sources. Fluid supply tubes (30, 40) leadto a valve assembly that includes actuation arms (24). Actuation arms(24) are pivotable to selectively change the state of the valveassembly. Based on the pivotal position of actuation arms (24), thevalve assembly is operable to selectively pinch or otherwise open/closethe supply of fluid from fluid supply tubes (30, 40) to lumen (104) ofneedle (100). Thus, actuation arms (24) are operable to selectivelycontrol the delivery of bleb fluid (340) and therapeutic agent (341) vianeedle (100). By way of example only, the valve assembly may beconfigured and operable in accordance with at least some of theteachings of U.S. Pub. No. 2015/0223977, entitled “Method and Apparatusfor Subretinal Administration of Therapeutic Agent,” published Aug. 13,2015, the disclosure of which is incorporated by reference herein. Othersuitable features and configurations that may be used to control fluiddelivery via needle (100) will be apparent to those of ordinary skill inthe art in view of the teachings herein.

It should be understood that the features and operability of instrument(10) may be varied in numerous ways. By way of example only, needle(100) may be replaced with needle (200) as described in greater detailbelow. In addition, cannula (50) may be replaced with cannula (400) aswill be described in greater detail below. In addition, instrument (10)may be modified in accordance with at least some of the teachings ofU.S. Pub. No. 2015/0223977, entitled “Method and Apparatus forSubretinal Administration of Therapeutic Agent,” published Aug. 13,2015, the disclosure of which is incorporated by reference herein; U.S.Pub. No. 2015/0351958, entitled “Therapeutic Agent Delivery Device withConvergent Lumen,” published Dec. 10, 2015, the disclosure of which isincorporated by reference herein; U.S. Pub. No. 2015/0351959, entitled“Sub-Retinal Tangential Needle Catheter Guide and Introducer,” publishedDec. 10, 2015, the disclosure of which is incorporated by referenceherein; U.S. Pub. No. 2016/0074212, entitled “Method and Apparatus forSensing Position Between Layers of an Eye,” published Mar. 17, 2016, thedisclosure of which is incorporated by reference herein; U.S. Pub. No.2016/0074217, entitled “Motorized Suprachoroidal Injection ofTherapeutic Agent,” published Mar. 17, 2016, the disclosure of which isincorporated by reference herein; U.S. Pub. No. 2016/0074211, entitled“Therapeutic Agent Delivery Device with Advanceable Cannula and Needle,”published Mar. 17, 2016, the disclosure of which is incorporated byreference herein; and/or U.S. Pub. No. 2016/0081849, entitled“Therapeutic Agent Delivery Device,” published Mar. 24, 2016, thedisclosure of which is incorporated by reference herein. Other suitablemodifications will be apparent to those of ordinary skill in the art inview of the teachings herein.

II. Exemplary Procedure for Subretinal Administration of TherapeuticAgent

FIGS. 4A-5C show an exemplary procedure for subretinal delivery oftherapeutic agent from a suprachoroidal approach using instrument (10)described above. By way of example only, the method described herein maybe employed to treat macular degeneration and/or other ocularconditions. Although the procedure described herein is discussed in thecontext of the treatment of age-related macular degeneration, it shouldbe understood that no such limitation is intended or implied. Forinstance, in some merely exemplary alternative procedures, the sametechniques described herein may be used to treat retinitis pigmentosa,diabetic retinopathy, and/or other ocular conditions. Additionally, itshould be understood that the procedure described herein may be used totreat either dry or wet age-related macular degeneration.

In the present example, the procedure begins by an operator immobilizingtissue surrounding a patient's eye (301) (e.g., the eyelids) using aspeculum, and/or any other instrument suitable for immobilization. Whileimmobilization described herein with reference to tissue surrounding eye(301), it should be understood that eye (301) itself may remain free tomove. Once the tissue surrounding eye (301) has been immobilized, an eyechandelier port (314) is inserted into eye (301), as shown in FIG. 4A,to provide intraocular illumination when the interior of eye (301) isviewed through the pupil. In the present example, eye chandelier port(314) is positioned in the inferior medial quadrant such that a superiortemporal quadrant sclerotomy may be preformed. Eye chandelier port (314)is positioned to direct light onto the interior of eye (301) toilluminate at least a portion of the retina (e.g., including at least aportion of the macula). As will be understood, such illuminationcorresponds to an area of eye (301) that is being targeted for deliveryof therapeutic agent.

In the present example, only chandelier port (314) is inserted at thestage shown in FIG. 4A, without yet inserting an optical fiber (315)into port (314). In some other versions, an optical fiber (315) may beinserted into chandelier port (314) at this stage. In either case, amicroscope may optionally be utilized to visually inspect the eye toconfirm proper positioning of eye chandelier port (314) relative to thetarget site. Although FIG. 4A shows a particular positioning of eyechandelier port (314), it should be understood that eye chandelier port(314) may have any other positioning as will be apparent to those ofordinary skill in the art in view of the teachings herein.

Once eye chandelier port (314) has been positioned, the sclera (304) maybe accessed by dissecting the conjunctiva by incising a flap in theconjunctiva and pulling the flap posteriorly. After such a dissection iscompleted, the exposed surface (305) of the sclera (304) may optionallybe blanched using a cautery tool to minimize bleeding. Once conjunctivadissection is complete, the exposed surface (305) of the sclera (304)may optionally be dried using a WECK-CEL or other suitable absorbentdevice. A template may then be used to mark eye (301), as described inU.S. Pub. No. 2015/0223977, entitled “Method and Apparatus forSubretinal Administration of Therapeutic Agent,” published Aug. 13,2015, the disclosure of which is incorporated by reference herein. Anoperator may then use a visual guide created using the template toattach a suture loop assembly (332) and to perform a sclerotomy, asshown in FIG. 4B, using a conventional scalpel (313) or other suitablecutting instrument. The sclerotomy procedure forms a small incisionthrough sclera (304) of eye (301). The sclerotomy is performed withparticular care to avoid penetration of the choroid (306). Thus, thesclerotomy procedure provides access to the space between sclera (304)and choroid (306). Once the incision is made in eye (301), a bluntdissection may optionally be performed to locally separate sclera (304)from choroid (306). Such a dissection may be performed using a smallblunt elongate instrument, as will be apparent to those of ordinaryskill in the art in view of the teachings herein.

With the sclerotomy procedure performed, an operator may insert cannula(50) of instrument (10) through incision (316) and into the spacebetween sclera (304) and choroid (306). As can be seen in FIG. 4C,cannula (50) is directed through suture loop assembly (332) and into theincision. Suture loop assembly (332) may stabilize cannula (50) duringinsertion. Additionally, suture loop assembly (332) maintains cannula(50) in a generally tangential orientation relative to the incision.Such tangential orientation may reduce trauma as cannula (50) is guidedthrough the incision. As cannula (50) is inserted into the incisionthrough suture loop assembly (332), an operator may use forceps or otherinstruments to further guide cannula (50) along an atraumatic path. Ofcourse, use of forceps or other instruments is merely optional, and maybe omitted in some examples.

Although not shown, it should be understood that in some examplescannula (50) may include one or more markers on the surface of cannula(50) to indicate various depths of insertion. While merely optional,such markers may be desirable to aid an operator in identifying theproper depth of insertion as cannula (50) is guided along an atraumaticpath. For instance, the operator may visually observe the position ofsuch markers in relation to suture loop assembly (332) and/or inrelation to the incision in the sclera (304) as an indication of thedepth to which cannula (50) is inserted in eye (301). By way of exampleonly, one such marker may correspond to an approximately 6 mm depth ofinsertion of cannula (50).

As shown in FIG. 4D, once cannula (50) is at least partially insertedinto eye (301), an operator may insert an optical fiber (315) into eyechandelier port (314) if the fiber (315) had not yet been inserted atthis stage. With eye chandelier port (314) in place and assembled withoptical fiber (315), an operator may activate eye chandelier port (314)by directing light through optical fiber (315) to provide illuminationof eye (301) and thereby visualize the interior of eye (301). Furtheradjustments to the positioning of cannula (50) may optionally be made atthis point to ensure proper positioning relative to the area ofgeographic atrophy of retina (308). In some instances, the operator maywish to rotate the eye (301), such as by pulling on suture loop assembly(332), to direct the pupil of the eye (301) toward the operator in orderto optimize visualization of the interior of the eye (301) via thepupil.

FIGS. 4C-4D show cannula (50) as it is guided between sclera (304) andchoroid (306) to the delivery site for the therapeutic agent. In thepresent example, the delivery site corresponds to a generally posteriorregion of eye (301) adjacent to an area of geographic atrophy of retina(308). In particular, the delivery site of the present example issuperior to the macula, in the potential space between the neurosensoryretina and the retinal pigment epithelium layer. By way of example only,the operator may rely on direct visualization through a microscopedirected through the pupil of eye (301) as cannula (50) is beingadvanced through the range of motion shown in FIGS. 4C-4D, withillumination provided through fiber (315) and port (314). Cannula (50)may be at least partially visible through a retina (308) and choroid(306) of eye (301). Visual tracking may be enhanced in versions where anoptical fiber is used to emit visible light through the distal end ofcannula (50).

Once cannula (50) has been advanced to the delivery site as shown inFIG. 4D, an operator may advance needle (100) of instrument (10) asdescribed above by actuating knob (26). As can be seen in FIGS. 4E and5A, needle (100) is advanced relative to cannula (50) such that needle(100) pierces through choroid (306) without penetrating retina (308).Immediately prior to penetrating choroid (306), needle (100) may appearunder direct visualization as “tenting” the surface of choroid (306). Inother words, needle (100) may deform choroid (306) by pushing upwardlyon choroid (306), providing an appearance similar to a tent poledeforming the roof of a tent. Such a visual phenomenon may be used by anoperator to identify whether choroid (306) is about to be pierced andthe location of any eventual piercing. The particular amount of needle(100) advancement sufficient to initiate “tenting” and subsequentpiercing of choroid (306) may be of any suitable amount as may bedetermined by a number of factors such as, but not limited to, generalpatient anatomy, local patient anatomy, operator preference, and/orother factors. As described above, a merely exemplary range of needle(100) advancement may be between approximately 0.25 mm and approximately10 mm; or more particularly between approximately 2 mm and approximately6 mm.

In the present example, after the operator has confirmed that needle(100) has been properly advanced by visualizing the tenting effectdescribed above, the operator infuses a balanced salt solution (BSS) orother similar solution as needle (100) is advanced relative to cannula(50). Such a BSS may form a leading bleb (340) ahead of needle (100) asneedle (100) is advanced through choroid (306). Leading bleb (340) maybe desirable for two reasons. First, as shown in FIGS. 4F and 5B,leading bleb (340) may provide a further visual indicator to an operatorto indicate when needle (100) is properly positioned at the deliverysite. Second, leading bleb (340) may provide a barrier between needle(100) and retina (308) once needle (100) has penetrated choroid (306).Such a barrier may push the retinal wall outwardly, thereby minimizingthe risk of retinal perforation as needle (100) is advanced to thedelivery site. In some versions, a foot pedal is actuated in order todrive leading bleb (340) out from needle (100). Alternatively, othersuitable features that may be used to drive leading bleb (340) out fromneedle (100) will be apparent to those of ordinary skill in the art inview of the teachings herein.

Once the operator visualizes leading bleb (340), the operator may ceaseinfusion of BSS, leaving a pocket of fluid as can be seen in FIGS. 4Fand 5B. Next, a therapeutic agent (341) may be infused by actuating asyringe or other fluid delivery device as described in variousreferences cited herein. The particular therapeutic agent (341)delivered may be any suitable therapeutic agent configured to treat anocular condition. Some merely exemplary suitable therapeutic agents mayinclude, but are not necessarily limited to, drugs having smaller orlarge molecules, therapeutic cell solutions, certain gene therapysolutions, tissue plasminogen activators, and/or any other suitabletherapeutic agent as will be apparent to those of ordinary skill in theart in view of the teachings herein. By way of example only, thetherapeutic agent (341) may be provided in accordance with at least someof the teachings of U.S. Pat. No. 7,413,734, entitled “Treatment ofRetinitis Pigmentosa with Human Umbilical Cord Cells,” issued Aug. 19,2008, the disclosure of which is incorporated by reference herein. Inaddition to, or as an alternative to, being used to deliver atherapeutic agent (341), instrument (10) and variations thereof may beused to provide drainage and/or perform other operations.

In the present example, the amount of therapeutic agent (341) that isultimately delivered to the delivery site is approximately 50 μL,although any other suitable amount may be delivered. In some versions, afoot pedal is actuated in order to drive agent (341) out from needle(100). Alternatively, other suitable features that may be used to driveagent (341) out from needle (100) will be apparent to those of ordinaryskill in the art in view of the teachings herein. Delivery oftherapeutic agent (341) may be visualized by an expansion of the pocketof fluid as can be seen in FIGS. 4G and 5C. As shown, therapeutic agent(341) essentially mixes with the fluid of leading bleb (340) astherapeutic agent (341) is injected into the surprachoroidal, subretinalspace.

Once delivery is complete, needle (100) may be retracted by rotatingknob (26) in a direction opposite to that used to advance needle (100);and cannula (50) may then be withdrawn from eye (301). It should beunderstood that because of the size of needle (100), the site whereneedle (100) penetrated through choroid (306) is self-sealing, such thatno further steps need be taken to seal the delivery site through choroid(306). Suture loop assembly (332) and chandelier (314) may be removed,and the incision in the sclera (304) may be closed using any suitableconventional techniques.

As noted above, the foregoing procedure may be carried out to treat apatient having macular degeneration. In some such instances, thetherapeutic agent (341) that is delivered by needle (100) may comprisecells that are derived from postpartum umbilicus and placenta. As notedabove, and by way of example only, the therapeutic agent (341) may beprovided in accordance with at least some of the teachings of U.S. Pat.No. 7,413,734, entitled “Treatment of Retinitis Pigmentosa with HumanUmbilical Cord Cells,” issued Aug. 19, 2008, the disclosure of which isincorporated by reference herein. Alternatively, needle (100) may beused to deliver any other suitable substance or substances, in additionto or in lieu of those described in U.S. Pat. No. 7,413,734 and/orelsewhere herein. By way of example only, therapeutic agent (341) maycomprise various kinds of drugs including but not limited to smallmolecules, large molecules, cells, and/or gene therapies. It should alsobe understood that macular degeneration is just one merely illustrativeexample of a condition that may be treated through the proceduredescribed herein. Other biological conditions that may be addressedusing the instruments and procedures described herein will be apparentto those of ordinary skill in the art.

It should also be understood that the procedure described above may becarried out in accordance with any of the teachings of U.S. Pub. No.2015/0223977, entitled “Method and Apparatus for SubretinalAdministration of Therapeutic Agent,” published Aug. 13, 2015, thedisclosure of which is incorporated by reference herein; U.S. Pub. No.2015/0351958, entitled “Therapeutic Agent Delivery Device withConvergent Lumen,” published Dec. 10, 2015, the disclosure of which isincorporated by reference herein; U.S. Pub. No. 2015/0351959, entitled“Sub-Retinal Tangential Needle Catheter Guide and Introducer,” publishedDec. 10, 2015, the disclosure of which is incorporated by referenceherein; U.S. Pub. No. 2016/0074212, entitled “Method and Apparatus forSensing Position Between Layers of an Eye,” published Mar. 17, 2016, thedisclosure of which is incorporated by reference herein; U.S. Pub. No.2016/0074217, entitled “Motorized Suprachoroidal Injection ofTherapeutic Agent,” published Mar. 17, 2016, the disclosure of which isincorporated by reference herein; U.S. Pub. No. 2016/0074211, entitled“Therapeutic Agent Delivery Device with Advanceable Cannula and Needle,”published Mar. 17, 2016, the disclosure of which is incorporated byreference herein; and/or U.S. Pub. No. 2016/0081849, entitled“Therapeutic Agent Delivery Device,” published Mar. 24, 2016, thedisclosure of which is incorporated by reference herein.

III. Exemplary Cannula Guides

As noted above, a suture loop assembly (332) may be installed in the eye(301) of a patient in order to stabilize and guide cannula (50) duringinsertion of cannula (50) into an incision (316) in the eye (301). Thoseof ordinary skill in the art will recognize that the formation of sutureloop assembly (332) may be somewhat time consuming. In addition, it maybe difficult to provide consistent spacing between the suture loops of asuture loop assembly (332); and between the suture loops and the eye(301). Such variations in spacing may yield variations in the entryangle and/or variations in the force required to insert cannula (50)through suture loop assembly (332). It may therefore be desirable toprovide a device that provides the stabilizing and guiding functionalityof suture loop assembly (332); yet that is faster and easier to installin the eye (301) than suture loop assembly (332), yielding moreconsistent results. Various illustrative examples of such devices aredescribed in greater detail below. These devices described below mayprovide faster installation times, minimize variability due to surgeontechnique, and require a lower level of expertise such that less surgeontraining will be necessary. At the end of the procedure, the device maybe removed from the eye such that no foreign body will be left in theeye.

A. Overview

FIGS. 6-7 show an exemplary guide tack (400) that may be used to guidecannula (50) through an incision (316) in the eye (301), instead ofusing suture loop assembly (332). Guide tack (400) of the presentexample comprises a head (420) with a pair of legs (410) extendingdownwardly from head (420). Guide tack (400) thus resembles an unformedstaple. Head (420) may be colored or otherwise marked to provide a highdegree of contrast between head (420) and the sclera (304). This maypromote easy visualization of head (420) when guide tack (400) isinstalled in the eye (301) as described below.

The free end of each leg (410) includes a sharp tip (412). By way ofexample only, legs (410) may be configured and operable similar toconventional vitrectomy trocars. By way of further example only, legs(410) may have a size corresponding to between 25 gauge and 30 gauge. Inthe present example, legs (410) extend from head (420) for a distance ofapproximately 3 mm. Such a leg (410) length may provide enough length toensure sufficient retention of legs (410) in the eye (301) whileminimizing the risk of contact with interior anatomy within the eye(301).

Sharp tips (412) enable legs (410) to pierce through the eye (301) suchthat tips (412) reach the vitreous chamber of the eye (301). Once legs(410) are inserted in the eye (310) friction may secure guide tack (400)to eye such that guide tack (400) is substantially anchored to the eye(301); yet enable guide tack (400) to be removed from the eye (301)without causing damage beyond the puncture sites created by legs (410).Moreover, the puncture sites created by legs (410) may be small enoughto be self-sealing after removal of guide tach (400) from the eye (301),such that no sutures are needed to seal the puncture sites. An exemplaryinstrument and procedure that may be employed to install guide tack(400) on the eye (301) will be described in greater detail below.

Head (420) of the present example defines a guide opening (422), a setof retainer pin openings (424), and a chamfer (428). Guide opening (422)is oriented along an axis that is transverse to the plane definedbetween legs (410). Guide pin opening (424) is dimensioned to slidablyyet snugly receive cannula (50) as will be described in greater detailbelow. Retainer pin openings (424) are oriented along an axis that isparallel to the longitudinal axes of legs (410). Retainer pin openings(424) are dimensioned to receive a retainer pin of a deploymentinstrument, as will also be described in greater detail below.

Chamfer (428) is configured to facilitate visualization of the site of asclerotomy adjacent to guide tack (400), as will be described in greaterdetail below. While only one chamfer (428) is provided in the presentexample, along only one of the upper edges of head (420), somevariations may provide two chamfers (428), along both of the upper edgesof head (420). Such dual chamfers may provide a symmetric configurationof head (420) (i.e., symmetry about a lateral axis) and further reducethe risk of head (420) impeding the view of the operator.

In some versions, the inner walls defining guide opening (422) areconfigured to provide a uniform cross-sectional size of guide opening(422) along the full depth of guide opening (422). In some otherversions, the inner walls defining guide opening (422) are configured toprovide a tapering profile in guide opening (422). Such a taperingprofile may provide a larger guide opening (422) size at the end ofguide opening (422) where cannula (50) is inserted; and a smaller guideopening (422) size at the end of guide opening (422) where cannula (50)exits. In such versions, chamfer (428) may be located at the side ofhead (420) corresponding to the smaller guide opening (422) size. Insuch versions, the operator may be instructed to orient guide tack (400)(or instrument (500) may be preloaded with guide tack (400)) such thatchamfer (428) will be on the side closest to the sclerotomy (514) asdescribed below. This will help ensure that the smaller guide opening(422) size is located on the side of guide tack (400) where cannula (50)will exit guide tack (400).

As also shown in FIGS. 6-7, the upper ends (426) of legs (410) areexposed relative to the top surface of head (420). In the presentexample, legs (410) are formed of a ferrous material (e.g., stainlesssteel, etc.), such that the exposed upper ends (426) may engage magnetsof a deployment instrument as will be described in greater detail below.By way of example only, guide tack (400) may be formed by molding head(420) out of a plastic material around the upper regions of legs (410).Various suitable materials and techniques that may be used to form guidetack (400) will be apparent to those of ordinary skill in the art inview of the teachings herein.

FIGS. 8A-8E show an exemplary procedure in which guide tack (400) isused to guide cannula (50) into a patient's eye (301) in order to reachthe position shown in FIGS. 4D-4G and 5A-5C, to perform the steps shownin FIGS. 4D-4G and 5A-5C as described above. As shown in FIG. 8A, thesclera of the patient's eye (301) is accessed by dissecting theconjunctiva by incising a flap in the conjunctiva and pulling the flapposteriorly. After such a dissection is completed, the exposed surface(305) of the sclera (304) may optionally be blanched using a cauterytool to minimize bleeding. Once conjunctiva dissection is complete, theexposed surface (305) of the sclera (304) may optionally be dried usinga WECK-CEL or other suitable absorbent device. A first end (502) of amarking and deployment instrument (500) is pressed against exposedsurface (305) to apply a pair of marks (510) to exposed surface (305).By way of example only, a pigment material may be first applied to firstend (502) (e.g., by pressing first end (502) against an ink pad), suchthat first end (502) leaves some of the pigment on exposed surface (305)to provide marks (510). Various exemplary configurations that may beused for marking and deployment instrument (500) will be described ingreater detail below. In the present example, marks (510) are located onthe pars plana region of the eye (301). In some versions, markingfeatures of first end (502) are also configured to facilitate locationof the pars plana region, by enabling the operator to identify theappropriate spacing from the limbus of the eye (301) corresponding tothe location of the pars plana.

As shown in FIG. 8B, the operator may then use a second end (504) ofmarking and deployment instrument (500) to install guide tack (400) ineye (301). In particular, the operator may align tips (412) with marks(510) and then press guide tack (400) toward eye (301), thereby piercingeye (301) with tips (412). The operator may further urge guide tack(400) toward eye (301) until the underside (430) of head (420) abutsexposed surface (305). The abutment of underside (430) with exposedsurface (305) will ensure consistent spacing between guide opening (422)and surface (305), such that the spacing should not vary from procedureto procedure.

As shown in FIG. 8C, when the operator removes marking and deploymentinstrument (500), guide tack (400) is anchored to the eye (301). Also, apair of additional marks (512) are left on exposed surface (305). In thepresent example, and as will be described in greater detail below,second end (504) of marking and deployment instrument (500) includes apair of marking elements next to the structure on which guide tack (400)is removably mounted, such that second end (504) applies marks (512) tothe eye (301) while simultaneously deploying guide tack (400) in the eye(301).

As shown in FIG. 8D, the operator then uses a conventional scalpel (520)to form a sclerotomy (514). The sclerotomy (514) is formed between marks(512), such that marks (512) are used to identify the ends of thesclerotomy (514). By way of example only, the sclerotomy (514) may beapproximately 3 mm long, extending center-to-center between marks (512).The sclerotomy (514) extends through the full scleral thickness,removing all scleral fibers. The sclerotomy (514) is performed withparticular care to avoid penetration of the choroid (306). Thus, thesclerotomy procedure provides access to the space between sclera (304)and choroid (306). Once the sclerotomy (514) is made in the eye (301), ablunt dissection may optionally be performed to locally separate sclera(304) from choroid (306). Such a dissection may be performed using asmall blunt elongate instrument, as will be apparent to those ofordinary skill in the art in view of the teachings herein.

After the sclerotomy (514) is formed, and as shown in FIG. 8E, cannula(50) is passed through guide opening (422) of guide tack (400) and thenthrough the sclerotomy (514). In particular, cannula (50) is insertedinto the space between the sclera (304) and the choroid (306). Asdescribed above, guide tack (400) may stabilize cannula (50).Additionally, guide tack (400) maintains cannula (50) in a generallytangential orientation relative to sclerotomy (514). Such tangentialorientation may reduce trauma as cannula (50) is guided throughsclerotomy (514) to stabilize cannula (50) and to prevent damage tosurrounding tissue. As cannula (50) is inserted into sclerotomy (514)through guide tack (400), the operator may use forceps or otherinstruments to further guide cannula (50) along an atraumatic path. Ofcourse, use of forceps or other instruments is merely optional, and maybe omitted in some examples.

As also shown in FIG. 8E, cannula (50) of the present example furtherincludes a depth marker (51) on the outer surface of cannula (50). Depthmarker (51) is configured such that the operator may visually observethe position of depth marker (51) in relation to guide tack (400) or inrelation to the sclerotomy (514) to determine when cannula (50) has beeninserted to a predetermined insertion depth. By way of example only,depth marker (510) may be positioned to correspond with an initialcannula (50) insertion depth of approximately 5 mm in relation to thesclerotomy (514). While cannula (50) only has one depth marker (51) inthe present example, alternative versions may include more than onedepth marker (51).

As yet another merely illustrative variation, cannula (50) may includean outwardly protruding depth stop feature that abuts guide tack (400)to physically restrict the depth of insertion of cannula (50) in the eye(301). In some such versions, the depth stop feature is configured toenable selective positioning of the depth stop feature along the lengthof cannula (50), such that the operator may select a desired depth ofinsertion before passing cannula (50) through guide opening (420).Again, one or more depth markers (51) may be used to assist the operatorin selecting a position for an adjustable depth stop feature along thelength of cannula (50). Various suitable forms that a depth stop featuremay take will be apparent to those of ordinary skill in the art in viewof the teachings herein.

After reaching the state shown in FIG. 8E, and after cannula (50) hasbeen inserted into the eye (301) to an appropriate depth, the proceduremay continue as described above with reference to FIGS. 4D-4G and 5A-5C.After the therapeutic agent (341) is injected into the surprachoroidal,subretinal space, cannula (500) may be withdrawn from the eye (301) andguide tack (400) may also be removed from the eye (301). The sclerotomy(514) may then be closed using any suitable conventional techniques. Asnoted above, the site where needle (100) penetrated through choroid(306) is self-sealing, such that no further steps need be taken to sealthe delivery site through choroid (306). As also noted above, the siteswhere legs (510) penetrated through the eye (301) are also self-sealing,such that no further steps need be taken to seal the puncture siteswhere legs (510) were inserted.

B. Guide Tack Variations

FIGS. 9-10 and 13-14 show another exemplary guide tack (600) that may beused in place of guide tack (400) described above. Except as otherwisedescribed below, guide tack (600) of this example may be configured andoperable just like guide tack (400). Guide tack (600) of this exampleincludes a head (620) with a pair of legs (610) extending downwardlyfrom head (620).

The free end of each leg (610) includes a sharp tip (612). As best seenin FIGS. 11-12, each sharp tip (612) has a tri-bevel configuration. Inparticular, sharp tip (612) includes a proximal facet (614) and a pairof distal facets (616, 618). All three facets (614, 616, 618) convergetogether at a first point (615), while distal facets (616, 618) alsoconverge at a second point (619). This tri-bevel configuration promotesrelatively easy piercing of the eye (301) as the operator urges sharptips (612) into the eye (301). Alternatively, sharp tips (612) may haveany other suitable configuration that enables sharp tips (612) to piercethe tissue layers of the eye (301), including but not limited to variouseye-piercing tip configurations known in the art. Legs (610) mayotherwise be configured just like legs (410) described above. It shouldalso be understood that the sharp tips of the legs of any of the otherguide tacks described herein may have the same tri-bevel configurationthat sharp tips (612) have.

Head (620) of the present example defines a guide opening (630) and achamfer (622). While not shown, head (620) may also include a retainerpin opening similar to retainer pin opening (424) described above. Inaddition, while not shown, the upper ends of legs (610) may be exposedat the top surface of head (620). Moreover, while only one chamfer (622)is shown, head (620) may instead have two chamfers (622) as describedherein. Guide opening (630) is sized and configured to slidably receivecannula (50). Guide opening (630) is oriented along an axis that istransverse to the plane defined between legs (610). Unlike guide opening(422) described above, guide opening (630) of the present example isopen along the bottom of guide opening (622).

As best seen in FIG. 14, guide opening (630) of the present example isformed by several flat surfaces (632, 634, 636, 638, 642, 644, 646,648). Surfaces (632, 634, 636, 638, 642, 644, 646, 648) are all orientedobliquely relative to the plane defined between legs (610); and relativeto planes that are perpendicular to the plane defined between legs(610). When viewed along the direction shown in FIG. 13, surfaces (632,634, 636, 638, 642, 644, 646, 648) are configured such that guideopening (630) deflects outwardly from the centerline of guide tack(600), at the mid-region of guide opening (630) along the height ofguide opening (630), along the plane defined between legs (610). Thisconfiguration may promote capture of cannula (50) within guide opening(630), ensuring that cannula (50) remains at an appropriate distancefrom the surface (305) of the sclera (304).

When viewed along the direction shown in FIG. 14, surfaces (632, 634,636, 638, 642, 644, 646, 648) are configured such that guide opening(630) deflects inwardly toward the centerline of guide tack (600), atthe mid-region of guide opening (630) along the height of guide opening(630), along a plane that is perpendicular to the plane defined betweenlegs (610). This configuration may minimize the amount of contactbetween cannula (50) and head (620), which may in turn minimize theamount of friction between cannula (50) and head (620) as cannula (50)is slid through guide opening (630). Reducing friction may reduce therisk of cannula (50) inadvertently pulling guide tack (600) from the eye(301) as cannula (50) is slid through guide opening (630). Despite thisminimization of contact between cannula (50) and head (620), surfaces(632, 634, 636, 638, 642, 644, 646, 648) may still provide sufficientcontact to maintain stability of cannula (50) when cannula (50) isdisposed in guide opening (630).

FIGS. 15-17 show another exemplary guide tack (700) that may be used inplace of guide tack (400) described above. Except as otherwise describedbelow, guide tack (700) of this example may be configured and operablejust like guide tack (400). Guide tack (700) of this example includes ahead (720) with a pair of legs (710) extending downwardly from head(720). The free end of each leg (710) includes a sharp tip (712). Sharptips (712) may be formed just like sharp tips (612). Alternatively,sharp tips (712) may have any other suitable configuration.

Head (720) of the present example defines a guide opening (722) and apair of chamfers (728). Guide opening (722) is sized and configured toslidably receive cannula (50). Guide opening (722) is oriented along anaxis that is transverse to the plane defined between legs (710). Unlikeguide opening (422) described above, guide opening (722) of the presentexample is open along the top of guide opening (722). However, a crownportion (714) of legs (710) extends through the open top of guideopening (722), effectively closing the top of guide opening (722). Insome versions, both legs (710) and crown portion (714) are formed of asingle monolithic piece of material. In some other versions, legs (710)and crown portion (714) are formed separately and are simply moldedtogether with head (720). Other suitable configurations and arrangementswill be apparent to those of ordinary skill in the art in view of theteachings herein.

FIGS. 18-20 show another exemplary guide tack (800) that may be used inplace of guide tack (400) described above. Except as otherwise describedbelow, guide tack (800) of this example may be configured and operablejust like guide tack (400). Guide tack (800) of this example includes ahead (820) with a pair of legs (810) extending downwardly from head(820). The free end of each leg (810) includes a sharp tip (812). Sharptips (812) may be formed just like sharp tips (612). Alternatively,sharp tips (812) may have any other suitable configuration.

Head (820) of the present example defines a guide opening (822),retainer pin openings (826), and a pair of chamfers (828). Guide opening(822) is sized and configured to slidably receive cannula (50). Guideopening (822) is oriented along an axis that is transverse to the planedefined between legs (810). Retainer pin openings (826) are orientedalong an axis that is parallel to the longitudinal axes of legs (810).Retainer pin openings (826) are dimensioned to receive a retainer pin ofa deployment instrument, as will also be described in greater detailbelow.

Head (820) of the present example further includes a pair of ribs (824)extending along the full length of guide opening (822), at the lateralsides of guide opening (822). Ribs (824) together define an effectivewidth (w) of opening (822). This width (w) is sized to closelycorrespond with the width of catheter (50), such that ribs (824)slidingly contact catheter (50) as catheter (50) is slid through opening(822). This configuration may minimize the amount of contact betweencannula (50) and head (820), which may in turn minimize the amount offriction between cannula (50) and head (820) as cannula (50) is slidthrough guide opening (822). Reducing friction may reduce the risk ofcannula (50) inadvertently pulling guide tack (800) from the eye (301)as cannula (50) is slid through guide opening (822). Despite thisminimization of contact between cannula (50) and head (820), ribs (824)may still provide sufficient contact to maintain stability of cannula(50) when cannula (50) is disposed in guide opening (822).

FIGS. 21-22 show another exemplary guide tack (900) that may be used inplace of guide tack (400) described above. Except as otherwise describedbelow, guide tack (900) of this example may be configured and operablejust like guide tack (400). Guide tack (900) of this example includes ahead (920) with a pair of legs (910) extending downwardly from head(920). The free end of each leg (910) includes a sharp tip (912). Sharptips (912) may be formed just like sharp tips (612). Alternatively,sharp tips (912) may have any other suitable configuration.

Head (820) of the present example defines a guide notch (922) and a pairof chamfers (928). Guide notch (922) is oriented along an axis that istransverse to the plane defined between legs (910). When guide tack(900) is secured to the eye (301), guide notch (922) is configured tocooperate with the surface (305) of the sclera (304) to define a guideopening. The guide opening defined by surface (305) and guide notch(922) is sized and configured to slidably receive cannula (50).

FIGS. 23-24 show an exemplary alternative head (1000) that may bereadily incorporated into any of the guide tacks (400) described herein.Head (1000) of this example includes retainer pin openings (1010), apair of leg openings (1012), a guide opening (1020), and a chamfer(1030). Retainer pin openings (1010) are oriented along an axis that isparallel to the longitudinal axes of legs that are disposed in legopenings (1012). Retainer pin openings (1010) are dimensioned to receivea retainer pin of a deployment instrument, as will also be described ingreater detail below. Leg openings (1012) are configured to receiverespective legs, which may be configured like any of the various guidetack legs described herein. Leg openings (1012) extend to the topsurface of head (1000), such that the upper ends of legs disposed in legopenings (1012) may be exposed relative to head (1000).

Guide opening (1020) is sized and configured to slidably receive cannula(50). Guide opening (1020) is oriented along an axis that is transverseto the plane defined between legs that are disposed in leg openings(1012). Head (1000) of the present example further includes a rib (1022)extending along the full length of guide opening (1020), at the upperside of guide opening (1020). Rib (1022) and the bottom surface of guideopening (1020) together define an effective height (h) of opening(1020). This height (h) is sized to closely correspond with thethickness of catheter (50), such that rib (1022) and the bottom surfaceof guide opening (1020) slidingly contact catheter (50) as catheter (50)is slid through opening (1020). This configuration may reduce the amountof contact between cannula (50) and head (1000), which may in turnreduce the amount of friction between cannula (50) and head (1000) ascannula (50) is slid through guide opening (1020). Reducing friction mayreduce the risk of cannula (50) inadvertently pulling a guide tackincorporating head (1000) from the eye (301) as cannula (50) is slidthrough guide opening (1020). Despite this reduction of contact betweencannula (50) and head (1050), rib (1022) and the bottom surface of guideopening (1020) may still provide sufficient contact to maintainstability of cannula (50) when cannula (50) is disposed in guide opening(1020).

FIGS. 25-28 show another exemplary alternative head (1050) that may bereadily incorporated into any of the guide tacks (400) described herein.Head (1050) of this example includes retainer pin openings (1052), apair of leg openings (1054), a guide opening (1060), and a chamfer(1070). Retainer pin openings (1052) are oriented along an axis that isparallel to the longitudinal axes of legs that are disposed in legopenings (1054). Retainer pin openings (1052) are dimensioned to receivea retainer pin of a deployment instrument, as will also be described ingreater detail below. Leg openings (1054) are configured to receiverespective legs, which may be configured like any of the various guidetack legs described herein. Leg openings (1054) extend to the topsurface of head (1050), such that the upper ends of legs disposed in legopenings (1054) may be exposed relative to head (1050).

Guide opening (1060) is sized and configured to slidably receive cannula(50). Guide opening (1060) is oriented along an axis that is transverseto the plane defined between legs that are disposed in leg openings(1054). Head (1050) of the present example further includes a pair ofribs (1062) extending along the full length of guide opening (1060), atthe lateral sides of guide opening (1060). Ribs (1062) together definean effective width (w) of opening (1060). This width (w) is sized toclosely correspond with the width of catheter (50), such that ribs(1062) slidingly contact catheter (50) as catheter (50) is slid throughopening (1062). This configuration may minimize the amount of contactbetween cannula (50) and head (1050), which may in turn minimize theamount of friction between cannula (50) and head (1050) as cannula (50)is slid through guide opening (1060). Reducing friction may reduce therisk of cannula (50) inadvertently pulling a guide tack incorporatinghead (1050) from the eye (301) as cannula (50) is slid through guideopening (1060). Despite this minimization of contact between cannula(50) and head (1050), ribs (1062) may still provide sufficient contactto maintain stability of cannula (50) when cannula (50) is disposed inguide opening (1060).

FIGS. 29-31 show additional exemplary configurations that may be used tosecure the legs of a guide tack to the head of a guide tack. Inparticular, FIG. 29 shows a guide tack (1100) where upper ends (1112) oflegs (1110) are bent inwardly toward each other, above a guide opening(1122) in head (1120). Head (1120) may be overmolded about bent upperends (1112) of legs (1110) to secure legs (1110) to head (1120). FIG. 30shows a guide tack (1150) where upper ends (1162) of legs (1160) arebent outwardly away from each other, near a guide opening (1172). Head(1170) may be overmolded about bent upper ends (1162) of legs (1160) tosecure legs (1160) to head (1170). FIG. 31 shows a guide tack (1200)where upper ends (1212) of legs (1210) are bent around pins (1224) inhead (1220), near a guide opening (1222). In this example, pins (1224)are oriented perpendicularly relative to the straight portions of legs(1160). Head (1220) may be overmolded about pins (1224) and bent upperends (1212) of legs (1212) to secure legs (1160) to head (1170).

It should be understood that any of the relationships between the legs(1110, 1162, 1210) and respective heads (1120, 1170, 1220) of guidetacks (1100, 1150, 1200) shown in FIGS. 29-31 may be readilyincorporated into any of the various guide tacks described herein. Othersuitable relationships that may be provided between the legs and headsof guide tacks will be apparent to those of ordinary skill in the art inview of the teachings herein.

FIGS. 32-33 show another exemplary guide tack (1250) that may be used inplace of guide tack (400) described above. Except as otherwise describedbelow, guide tack (1250) of this example may be configured and operablejust like guide tack (400). Guide tack (1250) of this example includes apair of legs (1260) with sharp tips (1262), a head portion (1270)defining a guide opening (1274), a guide ramp (1274), and a grasping tab(1276). Guide opening (1272) is sized and configured to slidably receivecannula (50). Guide opening (1272) is oriented along an axis that istransverse to the plane defined between legs (1260). Guide ramp (1274)is configured to stabilize guide tack (1250) against the surface (305)of the sclera (304) and assist in guiding cannula (50) into guideopening (1272). Grasping tab (1276) is configured to facilitate graspingand manipulation of guide tack (1250) with any suitable graspinginstrument. In some versions, guide tack (1250) is formed of milledsteel. Alternatively, any other suitable materials and processes may beused to form guide tack (1250).

FIGS. 34-35 show another exemplary guide tack (1300) that may be used inplace of guide tack (400) described above. Except as otherwise describedbelow, guide tack (1300) of this example may be configured and operablejust like guide tack (400). Guide tack (1300) of this example includes apair of legs (1310) with sharp tips (1312), a head portion (1320)defining a guide opening (1322), and a guide ramp (1324). Sharp tips(1312) are barbed in the present example, though this is merelyoptional. Guide opening (1322) is sized and configured to slidablyreceive cannula (50). Guide opening (1322) is oriented along an axisthat is transverse to the plane defined between legs (1310). Guide ramp(1324) is configured to stabilize guide tack (1300) against the surface(305) of the sclera (304) and assist in guiding cannula (50) into guideopening (1322). In some versions, guide tack (1300) is formed of milledsteel. Alternatively, any other suitable materials and processes may beused to form guide tack (1300).

IV. Exemplary Marking and Deployment Instruments

As noted above, a marking and deployment instrument (500) may be used toprovide the following three functions: mark the site where a guide tack(400) is to be installed in the eye (301), install the guide tack (400)at the marked site, and mark the site where a sclerotomy (514) is to beformed. The examples described below provide several forms that such aninstrument (500) may take. While the examples provided below provide allthree functions through a single instrument, the examples may be readilymodified to separate the functions among two instruments. For instance,a first instrument may be used to mark the site where a guide tack (400)is to be installed in the eye (301), while a second instrument may beused to install the guide tack (400) at the marked site and mark thesite where a sclerotomy (514) is to be formed. Other variations will beapparent to those of ordinary skill in the art in view of the teachingsherein. To the extent that examples described below refer specificallyto guide tack (400), the exemplary instruments described below (andvariations thereof) may alternatively be used with any of the variousguide tacks described herein.

FIGS. 36-41B show an exemplary marking and deployment instrument (1400).Instrument (1400) of this example includes a shaft (1402) having a firstend (1410) and a second end (1420). Shaft (1402) is sized and configuredto be easily grasped and manipulated by an operator's hand (e.g., usinga pencil grip), without requiring additional tools to grasp ormanipulate instrument (1400). As best seen in FIGS. 36 and 38, first end(1410) of shaft (1402) includes a pair of prongs (1412). While prongs(1412) are pointed in the present example, prongs (1412) are configuredto be atraumatic such that prongs (1412) will not pierce the sclera(304) when prongs (1412) are urged against the surface (305) of thesclera (304) to mark the surface (305) as described herein.

In some versions, prongs (1412) are positioned such that the spacingbetween prongs (1412) corresponds with the spacing between the limbus ofthe eye (301) and the pars plana of the eye (301). In such versions, asnoted above, since the guide tack (400) is to be deployed at the parsplana region, the operator may use first end (1410) to determine thelocation of the appropriate region to deploy guide tack (400). Inaddition, or in the alternative, prongs (1412) may be positioned suchthat the spacing between prongs (1412) corresponds with the spacingbetween legs (410) of guide tack (400). Thus, prongs (1412) may be usedto mark the insertion points for legs (410). In particular, the operatormay first press prongs (1412) against an inkpad, and then press prongs(1412) against surface (305) of sclera (304) to leave markings (510) asdescribed above with reference to FIG. 8A.

As best seen in FIGS. 37 and 39, second end (1420) includes a pair ofprongs (1422), a retention pin (1424), and a pair of magnets (1428).While prongs (1422) are pointed in the present example, prongs (1422)are configured to be atraumatic such that prongs (1422) will not piercethe sclera (304) when prongs (1422) are urged against the surface (305)of the sclera (304) to mark the surface (305) as described herein.Prongs (1422) are positioned such that the spacing between prongs (1422)corresponds with an appropriate length of a sclerotomy (514) to receivecannula (50). For instance, prongs (1412) may be positioned such thatprongs (1422) are spaced apart by approximately 3 mm, center to center.Thus, prongs (1422) may be used to mark the site of a sclerotomy (514).In particular, the operator may first press prongs (1422) against aninkpad, and then press prongs (1422) against surface (305) of sclera(304) to leave markings (512) as described above with reference to FIG.8C.

Retention pin (1424) is configured to fit in the retention pin openingsof a guide tack. In particular, retention pin (1424) is configured toprovide friction with the retention pin openings of a guide tack, suchthat the guide tack is removably secured to second end (1420) viafrictional engagement with retention pin (1424). An example of suchengagement is shown in FIG. 40, where retention pin (1424) is disposedin both retention pin openings (424). Magnets (1428) are positioned tocorrespond with the locations of exposed upper ends (426) of legs (410).Since legs (410) are formed of a ferrous material in this example,magnets (1428) thus further removably secure guide tack (400) to secondend (1420). In variations where the upper ends of the legs of the guidetack are not exposed, magnets (1428) may still provide sufficientmagnetic attraction to releasably retain the guide tack on second end(1420). It should also be understood that some variations of instrument(1400) may lack retention pin (1424) while still having magnets (1428);or lack magnets (1428) while still having retention pin (1424).

As shown in FIGS. 41A-41B, retention pin (1424) is secured to a slider(1426) in the present example. Slider (1426) is slidable relative toshaft (1402) between a distal position (FIG. 41A) and a proximalposition (FIG. 41B). In versions where the guide tack has retention pinopenings, slider (1426) and retention pin (1424) may be distallypositioned while the guide tack is secured to second end (1420). Whenthe operator wishes to release the guide tack from second end (1420)(e.g., when the legs of the guide tack are fully inserted into the eye(301) and the head of the guide tack is abutting the surface (305) ofthe sclera (304)), the operator may retract slider (1426) proximally toretract retention pin (1424) proximally, thereby forcing disengagementbetween retention pin (1424) and the retention pin openings of the guidetack. Friction between the legs of the guide tack and the sclera (304)will be stronger than the attractive forces between magnets (1428) andthe ferrous components of the guide tack (e.g., the upper ends of thelegs of the guide tack), such that the guide tack will remain secured tothe eye (301) as the operator pulls instrument (1400) away from theguide tack.

In versions where the guide tack lacks retention pin openings, slider(1426) and retention pin (1424) may be proximally positioned while theguide tack is secured to second end (1420) via magnetic attractionbetween magnets (1428) and ferrous components of the guide tack. Whenthe operator wishes to release the guide tack from second end (1420)(e.g., when the legs of the guide tack are fully inserted into the eye(301) and the head of the guide tack is abutting the surface (305) ofthe sclera (304)), the operator may advance slider (1426) distally toadvance retention pin (1424) distally, while simultaneously pullinginstrument (1400) proximally, thereby pushing the guide tack away frommagnets (1428). Friction between the legs of the guide tack and thesclera (304) will ensure that the guide tack will remain secured to theeye (301) as the operator pulls instrument (1400) away from the guidetack to disengage the guide tack.

FIGS. 42-43 show another exemplary marking and deployment instrument(1500). Instrument (1500) of this example includes a shaft (1502) havinga first end (1510) and a second end (1520). First end (1510) has a setof prongs (1512) that are configured and operable just like prongs(1512) described above. Second end (1520) has a set of prongs (1522)that are configured and operable just like prongs (1422) describedabove. Second end (1520) also has a pair of magnets (1528) that areconfigured and operable just like magnets (1428) described above. Unlikeinstrument (1400), instrument (1500) of this example lacks retention pin(1424) and slider (1426). Instrument (1500) of this example thus reliessolely on magnets (1528) to releasably secure a guide tack to second end(1520).

In some variations of instrument (1500), for use with guide tacks thatinclude retention pin openings, second end (1520) includes a stationaryretention pin that is not capable of advancing or retracting relative toshaft (1502). In such variations, friction between the legs of the guidetack and the sclera (304) may be stronger than the friction between theretention pin of instrument (1500) and the retention pin openings of theguide tack. In variations of instrument (1500) that have a stationaryretention pin, magnets (1528) may still be included or magnets (1528)may be omitted.

FIGS. 44-47 show various examples of marking heads that may beincorporated into any suitable marking instrument. In some versions,these marking heads are provided at one end of a marking and deploymentinstrument, where the other end of the instrument is configured toremovably secure and deploy a guide tack. In some other versions, thesemarking heads are provided at the end of an instrument that is dedicatedsolely to marking, such that the instrument lacks features that areconfigured to removably secure and deploy a guide tack.

In the example shown in FIG. 44, a marking head (1600) includes a firstprong (1602), a pair of second prongs (1603), an oblong marking feature(1604), and a pair of third prongs (1606). First prong (1602) isconfigured to be positioned at the limbus of the eye (301) and therebyserve as a positional reference for the other prongs (1603, 1606) andmarking feature (1604) of marking head (1600). Second prongs (1603) arepositioned and spaced to correspond with the location and length of thesclerotomy (514). Third prongs (1606) are positioned and spaced tocorrespond with the location and spacing of the legs of the guide tack.Third prongs (1606) are thus positioned to correspond with the locationof the pars plana when first prong (1602) is positioned on the limbus.Oblong marking feature (1604) is sized and configured to correspond withthe configuration of the head of the guide tack. Oblong marking feature(1604) surrounds third prongs (1606).

In use, the operator may press marking head (1600) against an inkpad,then position first prong (1602) at the limbus of the eye (301) andpress marking head (1600) against the surface (305) of the sclera (304).The operator may then observe the positions of the markings left bythird prongs (1606) and insert the legs of the guide tack at thelocations of those markings. When the guide tack is fully seated againstthe surface (305) of the sclera (304), the operator may verify properpositioning by observing correspondence between the marking left byoblong marking feature (1604) and the head of the guide tack. Theoperator may then form the sclerotomy (314) by using a scalpel to cutbetween the markings left by second prongs (1603).

In the example shown in FIG. 45, a marking head (1650) includes a firstprong (1652), a pair of second prongs (1653), a pair of third prongs(1654), and an oblong marking feature (1656). First prong (1652) isconfigured to be positioned at the limbus of the eye (301) and therebyserve as a positional reference for the other prongs (1653, 1654) andmarking feature (1656) of marking head (1650). Second prongs (1653) arepositioned and spaced to correspond with the location and length of thesclerotomy (514). Third prongs (1654) are positioned and spaced tocorrespond with the location and spacing of the legs of the guide tack.Third prongs (1654) are thus positioned to correspond with the locationof the pars plana when first prong (1652) is positioned on the limbus.Oblong marking feature (1656) extends between third prongs (1654).

In use, the operator may press marking head (1650) against an inkpad,then position first prong (1652) at the limbus of the eye (301) andpress marking head (1650) against the surface (305) of the sclera (304).The operator may then observe the positions of the markings left bythird prongs (1654) and insert the legs of the guide tack at thelocations of those markings. The marking left by oblong marking feature(1656) may assist in emphasizing the positions of the markings left bythird prongs (1654). When the guide tack is fully seated against thesurface (305) of the sclera (304), the operator may then form thesclerotomy (314) by using a scalpel to cut between the markings left bysecond prongs (1653).

In the example shown in FIG. 46, a marking head (1700) includes a firstprong (1702), a pair of second prongs (1703), and a pair of third prongs(1704). First prong (1702) is configured to be positioned at the limbusof the eye (301) and thereby serve as a positional reference for theother prongs (1703, 1704) of marking head (1600). Second prongs (1703)are positioned and spaced to correspond with the location and length ofthe sclerotomy (514). Third prongs (1704) are positioned and spaced tocorrespond with the location and spacing of the legs of the guide tack.Third prongs (1704) are thus positioned to correspond with the locationof the pars plana when first prong (1702) is positioned on the limbus.

In use, the operator may press marking head (1700) against an inkpad,then position first prong (1702) at the limbus of the eye (301) andpress marking head (1700) against the surface (305) of the sclera (304).The operator may then observe the positions of the markings left bythird prongs (1704) and insert the legs of the guide tack at thelocations of those markings. When the guide tack is fully seated againstthe surface (305) of the sclera (304), the operator may then form thesclerotomy (314) by using a scalpel to cut between the markings left bysecond prongs (1703).

In the example shown in FIG. 47, a marking head (1750) includes a firstprong (1752), a pair of second prongs (1754), an oblong marking feature(1756), and a pair of third prongs (1758). First prong (1752) isconfigured to be positioned at the limbus of the eye (301) and therebyserve as a positional reference for the other prongs (1754, 1758) andmarking feature (1756) of marking head (1750). Second prongs (1754) arepositioned and spaced to correspond with the location and length of thesclerotomy (514). Third prongs (1758) are positioned and spaced tocorrespond with the location and spacing of the legs of the guide tack.Third prongs (1758) are thus positioned to correspond with the locationof the pars plana when first prong (1752) is positioned on the limbus.Oblong marking feature (1756) is sized and configured to correspond withthe configuration of the head of the guide tack. Oblong marking feature(1756) surrounds third prongs (1758).

Marking head (1750) is configured and operable just like marking head(1600), except that prongs (1603) have a circular cross-sectionalprofile while prongs (1754) have a triangular cross-sectional profile.The triangular cross-sectional profiles of prongs (1754) are orientedsuch that edges of prongs (1754) are pointed toward each other. Thisconfiguration and orientation of prongs (1754) may provide a more easilydiscernible visual indication of where sclerotomy (514) should beformed.

FIGS. 48-55 show various exemplary marking patterns that may be appliedto a patient's eye (301) using a marking instrument. By way of exampleonly, such marking patterns may be applied using an instrument that hasone end dedicated to marking the patient's eye (301) and another enddedicated to deploying a guide tack in the patient's eye (301). Asanother merely illustrative example, such marking patterns may beapplied using an instrument that is dedicated solely to marking, suchthat the instrument lacks features that are configured to removablysecure and deploy a guide tack.

FIG. 48 shows a marking pattern (1800) that includes a top dot (1804)and additional dots (1802). Top dot (804) is located at the limbus, thelower pair of dots (1802) are located at positions corresponding to theends of a sclerotomy site, and the upper pair of dots (1802) are locatedat positions corresponding to insertion points for legs of a guide tack.

FIG. 49 shows a marking pattern (1810) that includes a top dot (1816),additional dots (1812), and a line (1814). Top dot (1816) is located atthe limbus, dots (1812) are located at positions corresponding to theends of a sclerotomy site, and line (1814) is located at positionscorresponding to insertion points for legs of a guide tack.

FIG. 50 shows a marking pattern (1820) that includes a top dot (1826),additional dots (1822), and a line (1824). Top dot (1826) is located atthe limbus, the lower pair of dots (1822) are located at positionscorresponding to the ends of a sclerotomy site, and the upper pair ofdots (1822) are located at positions corresponding to insertion pointsfor legs of a guide tack. Line (1824) is positioned between the upperpair of dots (1822) thereby visually emphasizing the position of upperpair of dots (1822).

FIG. 51 shows a marking pattern (1830) that includes a top dot (1836),additional dots (1832), and a hollow oblong mark (1834). Top dot (1836)is located at the limbus, dots (1832) are located at positionscorresponding to the ends of a sclerotomy site, and oblong mark (1834)is located at positions corresponding to insertion points for legs of aguide tack.

FIG. 52 shows a marking pattern (1840) that includes several dots (1842,1844, 1846). Pattern (1840) is identical to pattern (1840) except thatdots (1844) are hollow (i.e., circles); whereas the upper pair of dots(1802) are solid.

FIG. 53 shows a marking pattern (1850) that includes several dots (1852,1856) and an oblong mark (1854). Pattern (1850) is identical to pattern(1830), except that oblong mark (1854) is rectangular; whereas oblongmark (1834) is shaped like an oval or flattened ellipse.

FIG. 54 shows a marking pattern (1860) that includes several dots (1862,1866) and an oblong mark (1864). Pattern (1860) is identical to pattern(1810), except that oblong mark (1864) is rectangular; whereas oblongmark (1814) is shaped like an oval or flattened ellipse.

FIG. 55 shows a marking pattern (1870) that includes several dots (1862,1866, 1868) and a line (1864). Pattern (1870) is identical to pattern(1820) except that dots (1866) are hollow (i.e., circles); whereas theupper pair of dots (1822) are solid.

V. Exemplary Combinations

The following examples relate to various non-exhaustive ways in whichthe teachings herein may be combined or applied. It should be understoodthat the following examples are not intended to restrict the coverage ofany claims that may be presented at any time in this application or insubsequent filings of this application. No disclaimer is intended. Thefollowing examples are being provided for nothing more than merelyillustrative purposes. It is contemplated that the various teachingsherein may be arranged and applied in numerous other ways. It is alsocontemplated that some variations may omit certain features referred toin the below examples. Therefore, none of the aspects or featuresreferred to below should be deemed critical unless otherwise explicitlyindicated as such at a later date by the inventors or by a successor ininterest to the inventors. If any claims are presented in thisapplication or in subsequent filings related to this application thatinclude additional features beyond those referred to below, thoseadditional features shall not be presumed to have been added for anyreason relating to patentability.

Example 1

An apparatus, comprising: (a) a body, wherein the body includes anengagement feature configured to engage a deployment instrument; and (b)a pair of rigid legs extending from the body, wherein the legs areparallel with each other, wherein each leg has a sharp tip, wherein thelegs both extend along a plane; wherein the body defines a guideopening, wherein the guide opening is oriented transversely relative tothe plane associated with the legs, wherein the guide opening is sizedto receive a cannula having a generally flat profile.

Example 2

The apparatus of Example 1, wherein the engage feature comprises a firstretaining pin opening, wherein the first retaining pin opening isconfigured to receive a retaining pin of a deployment instrument.

Example 3

The apparatus of Example 2, wherein the engage feature further comprisesa second retaining pin opening, wherein the second retaining pin openingis further configured to receive a retaining pin of a deploymentinstrument.

Example 4

The apparatus of Example 3, wherein the first and second retaining pinopenings are coaxially aligned with each other.

Example 5

The apparatus of any one or more of Examples 3 through 4, wherein thefirst retaining pin opening is located at an upper side of the guideopening, wherein the second retaining pin opening is located at a bottomside of the guide opening.

Example 6

The apparatus of any one or more of Examples 1 through 5, wherein thebody has an upper surface and a lower surface, wherein the legs extendfrom the lower surface, wherein each leg has an upper end that isexposed relative to the upper surface.

Example 7

The apparatus of Example 6, wherein the legs comprise a ferrousmaterial.

Example 8

The apparatus of any one or more of Examples 1 through 7, wherein thebody further includes at least one chamfer.

Example 9

The apparatus of any one or more of Examples 1 through 8, wherein thebody further includes at least one rib in the guide opening, wherein theat least one rib is configured to reduce contact between the guide and acannula disposed in the guide opening.

Example 10

The apparatus of Example 9, wherein the at least one rib is positionedon an upper side of the guide opening.

Example 11

The apparatus of Example 9, wherein the at least one rib comprises apair of ribs positioned on opposite lateral sides of the guide opening.

Example 12

The apparatus of any one or more of Examples 1 through 11, wherein thebody further includes at least one chamfered surface leading into theguide opening.

Example 13

The apparatus of any one or more of Examples 1 through 12, wherein thelegs have straight lower portions and bent upper portions, wherein thestraight lower portions include the sharp tips, wherein the bent upperportions are located in the body.

Example 14

The apparatus of Example 13, wherein the bent upper portions are bentoutwardly relative to a centerline of the body.

Example 15

The apparatus of any one or more of Examples 1 through 14, furthercomprising an applier instrument, wherein the applier instrumentcomprises: (i) a shaft, and (ii) a head portion located at an end of theshaft, wherein the head portion comprises: (A) an engagement featureconfigured to releasably engage the engagement feature of the body, and(B) a marking feature configured to mark a sclerotomy site on an eye.

Example 16

The apparatus of Example 15, wherein the engagement feature comprises aretaining pin.

Example 17

The apparatus of any one or more of Examples 15 through 16, wherein theengagement feature comprises one or more magnets.

Example 18

An apparatus, comprising: (a) a shaft having a first end and a secondend; (b) a first marking element at the first end, wherein the firstmarking element includes prongs configured to define a spacingcorresponding to either or both of; (i) a distance between a limbus anda pars plana, or (ii) legs of a guide tack; (c) a second marking elementat the second end, wherein the second marking element includes prongsconfigured to define ends of a sclerotomy site; and (d) a guide tackretaining feature at the second end, wherein the guide tack retainingfeature is configured to releasably retain a guide tack.

Example 19

A method of inserting a cannula into an eye of a patient, the methodcomprising: (a) inserting legs of a guide tack into a pars plana regionof the eye, wherein the guide tack further includes a head secured toupper ends of the legs, wherein the head defines a guide openingoriented transversely relative to a plane defined between the legs; (b)forming a sclerotomy near the guide tack; (c) inserting a cannulathrough the guide opening; and (d) inserting the cannula through thesclerotomy, wherein the guide tack is configured to guide the cannulathrough the scelrotomy at a substantially tangential orientation.

Example 20

The method of Example 19, further comprising marking the sclerotomy sitewith a marking and deployment instrument, wherein the act of insertingthe legs of the guide tack into the pars plana region of the eye is alsoperformed with the marking and deployment instrument simultaneously withthe act of marking the sclerotomy site, wherein the act of forming thesclerotomy is performed using marks formed by the act of marking thesclerotomy site.

VI. Miscellaneous

In the examples described above, the legs of the guide tacks areparallel with each other; and perpendicular relative to the head of thetack. In some variations, the legs of the guide tacks may be splayedinwardly or outwardly, such that the legs are not parallel with eachother; and such that the legs are obliquely oriented relative to thehead of the tack. In such variations, the legs may be resiliently biasedto assume such splayed configurations; yet be deformable to assume aparallel configuration (e.g., during insertion of the legs into the eye(301)). Such splaying of the legs may further promote retention of theguide tack in the eye (301).

The guide tacks described herein may be used with devices and inprocedures as described in U.S. Pat. App. No. [ATTORNEY DOCKET NO.END8061USNP.0614018], entitled “Apparatus and Method to Form Entry Blebfor Subretinal Delivery of Therapeutic Agent,” filed on even dateherewith, the disclosure of which is incorporated by reference herein;and/or of U.S. Pat. App. No. [ATTORNEY DOCKET NO. END8063USNP.0648024],entitled “Injection Device for Subretinal Delivery of TherapeuticAgent,” filed on even date herewith, the disclosure of which isincorporated by reference herein. Alternatively, the guide tacksdescribed herein may be used with any other suitable devices and or inany other suitable procedures.

It should be understood that any of the versions of the instrumentsdescribed herein may include various other features in addition to or inlieu of those described above. By way of example only, any of thedevices herein may also include one or more of the various featuresdisclosed in any of the various references that are incorporated byreference herein.

It should be understood that any one or more of the teachings,expressions, embodiments, examples, etc. described herein may becombined with any one or more of the other teachings, expressions,embodiments, examples, etc. that are described herein. Theabove-described teachings, expressions, embodiments, examples, etc.should therefore not be viewed in isolation relative to each other.Various suitable ways in which the teachings herein may be combined willbe readily apparent to those of ordinary skill in the art in view of theteachings herein. Such modifications and variations are intended to beincluded within the scope of the claims.

It should be appreciated that any patent, publication, or otherdisclosure material, in whole or in part, that is said to beincorporated by reference herein is incorporated herein only to theextent that the incorporated material does not conflict with existingdefinitions, statements, or other disclosure material set forth in thisdisclosure. As such, and to the extent necessary, the disclosure asexplicitly set forth herein supersedes any conflicting materialincorporated herein by reference. Any material, or portion thereof, thatis said to be incorporated by reference herein, but which conflicts withexisting definitions, statements, or other disclosure material set forthherein will only be incorporated to the extent that no conflict arisesbetween that incorporated material and the existing disclosure material.

Versions described above may be designed to be disposed of after asingle use, or they can be designed to be used multiple times. Versionsmay, in either or both cases, be reconditioned for reuse after at leastone use. Reconditioning may include any combination of the steps ofdisassembly of the device, followed by cleaning or replacement ofparticular pieces, and subsequent reassembly. In particular, someversions of the device may be disassembled, and any number of theparticular pieces or parts of the device may be selectively replaced orremoved in any combination. Upon cleaning and/or replacement ofparticular parts, some versions of the device may be reassembled forsubsequent use either at a reconditioning facility, or by an operatorimmediately prior to a procedure. Those skilled in the art willappreciate that reconditioning of a device may utilize a variety oftechniques for disassembly, cleaning/replacement, and reassembly. Use ofsuch techniques, and the resulting reconditioned device, are all withinthe scope of the present application.

By way of example only, versions described herein may be sterilizedbefore and/or after a procedure. In one sterilization technique, thedevice is placed in a closed and sealed container, such as a plastic orTYVEK bag. The container and device may then be placed in a field ofradiation that can penetrate the container, such as gamma radiation,x-rays, or high-energy electrons. The radiation may kill bacteria on thedevice and in the container. The sterilized device may then be stored inthe sterile container for later use. A device may also be sterilizedusing any other technique known in the art, including but not limited tobeta or gamma radiation, ethylene oxide, or steam.

Having shown and described various embodiments of the present invention,further adaptations of the methods and systems described herein may beaccomplished by appropriate modifications by one of ordinary skill inthe art without departing from the scope of the present invention.Several of such potential modifications have been mentioned, and otherswill be apparent to those skilled in the art. For instance, theexamples, embodiments, geometrics, materials, dimensions, ratios, steps,and the like discussed above are illustrative and are not required.Accordingly, the scope of the present invention should be considered interms of the following claims and is understood not to be limited to thedetails of structure and operation shown and described in thespecification and drawings.

I/We claim:
 1. An apparatus, comprising: (a) a body, wherein the bodyincludes an engagement feature configured to engage a deploymentinstrument; and (b) a pair of rigid legs extending from the body,wherein the legs are parallel with each other, wherein each leg has asharp tip, wherein the legs both extend along a plane; wherein the bodydefines a guide opening, wherein the guide opening is orientedtransversely relative to the plane associated with the legs, wherein theguide opening is sized to receive a cannula having a generally flatprofile.
 2. The apparatus of claim 1, wherein the engage featurecomprises a first retaining pin opening, wherein the first retaining pinopening is configured to receive a retaining pin of a deploymentinstrument.
 3. The apparatus of claim 2, wherein the engage featurefurther comprises a second retaining pin opening, wherein the secondretaining pin opening is further configured to receive a retaining pinof a deployment instrument.
 4. The apparatus of claim 3, wherein thefirst and second retaining pin openings are coaxially aligned with eachother.
 5. The apparatus of claim 3, wherein the first retaining pinopening is located at an upper side of the guide opening, wherein thesecond retaining pin opening is located at a bottom side of the guideopening.
 6. The apparatus of claim 1, wherein the body has an uppersurface and a lower surface, wherein the legs extend from the lowersurface, wherein each leg has an upper end that is exposed relative tothe upper surface.
 7. The apparatus of claim 6, wherein the legscomprise a ferrous material.
 8. The apparatus of claim 1, wherein thebody further includes at least one chamfer.
 9. The apparatus of claim 1,wherein the body further includes at least one rib in the guide opening,wherein the at least one rib is configured to reduce contact between theguide and a cannula disposed in the guide opening.
 10. The apparatus ofclaim 9, wherein the at least one rib is positioned on an upper side ofthe guide opening.
 11. The apparatus of claim 9, wherein the at leastone rib comprises a pair of ribs positioned on opposite lateral sides ofthe guide opening.
 12. The apparatus of claim 1, wherein the bodyfurther includes at least one chamfered surface leading into the guideopening.
 13. The apparatus of claim 1, wherein the legs have straightlower portions and bent upper portions, wherein the straight lowerportions include the sharp tips, wherein the bent upper portions arelocated in the body.
 14. The apparatus of claim 13, wherein the bentupper portions are bent outwardly relative to a centerline of the body.15. The apparatus of claim 1, further comprising an applier instrument,wherein the applier instrument comprises: (i) a shaft, and (ii) a headportion located at an end of the shaft, wherein the head portioncomprises: (A) an engagement feature configured to releasably engage theengagement feature of the body, and (B) a marking feature configured tomark a sclerotomy site on an eye.
 16. The apparatus of claim 15, whereinthe engagement feature comprises a retaining pin.
 17. The apparatus ofclaim 15, wherein the engagement feature comprises one or more magnets.18. An apparatus, comprising: (a) a shaft having a first end and asecond end; (b) a first marking element at the first end, wherein thefirst marking element includes prongs configured to define a spacingcorresponding to either or both of: (i) a distance between a limbus anda pars plana, or (ii) legs of a guide tack; (c) a second marking elementat the second end, wherein the second marking element includes prongsconfigured to define ends of a sclerotomy site; and (d) a guide tackretaining feature at the second end, wherein the guide tack retainingfeature is configured to releasably retain a guide tack.
 19. A method ofinserting a cannula into an eye of a patient, the method comprising: (a)inserting legs of a guide tack into a pars plana region of the eye,wherein the guide tack further includes a head secured to upper ends ofthe legs, wherein the head defines a guide opening oriented transverselyrelative to a plane defined between the legs; (b) forming a sclerotomynear the guide tack; (c) inserting a cannula through the guide opening;and (d) inserting the cannula through the sclerotomy, wherein the guidetack is configured to guide the cannula through the scelrotomy at asubstantially tangential orientation.
 20. The method of claim 19,further comprising marking the sclerotomy site with a marking anddeployment instrument, wherein the act of inserting the legs of theguide tack into the pars plana region of the eye is also performed withthe marking and deployment instrument simultaneously with the act ofmarking the sclerotomy site, wherein the act of forming the sclerotomyis performed using marks formed by the act of marking the sclerotomysite.